Electric flash bulb for use as
indicator

ABSTRACT

Mixture agents consisting of mixed coloring agents and oxidizing agents are enclosed in a light pervious envelope of glass or similar material of an electric flash bulb. The coloring agents thereof are adhered to the inside wall of the flash bulb by ignition of combustible material within the bulb, whereby the envelope of the flash bulb is colored and may be used as an indicator in the maintenance of certain equipment.

United States Patent 1191 UNITED STATES PATENTS De Boer 431/94 Ohmae et al. 1 June 28, 1974 [541 ELECTRIC FLASH BULB FOR USE AS 3,156,107 11/1964 Shaffer 431/94 INDICATOR 3,242,701 3/1966 Shaffer 431/94 4 3,586,470 6/1971 Brown 431/13 [75] I ento enn Ohmae; e m d 3,586,471 6/1971 McDonough et al 431/13 Hisashi Nikkawa, all of Yokohama, 3,609,331 9/1971 Fink et a1 431/13 Japan 3,625,640 12/1971 Shaffer 431/13 [73] Assignees Tokyo Shibaura Electric Company Limited, Ken, Japan 4 Primary Examiner-Carroll B. Dority, Jr. Attorney, Agent, or Firm-Oblon, Fisher, Spivak, Me- [22] F1led. Apr. 10, 1972 Cleuand & Maier [21] Appl. No.: 242,398

1 [30] Foreign Application Priority Data [57] ABSTRACT Apr. 10, 1971 Japan 46-22583 Mixture agents consisting of Coloring agents Apr. 10, 1971 Japan 46-27|05 and oxidizing agents are enclosed in a pervious envelope of glass or similar material of an electric [52] US. Cl. 431/lFl3343;/%21 flash bulb The coloring agents thereof are adhered to lift. Cl. 3 the inside wall of the flash ignition of combus Fleld Of Search... 4 tible material hi the bulb, whereby the envelope References Cited of the flash bulb is colored and may be used as an indicator in the maintenance of certain equipment.

8 Claims, 6 Drawing Figures ELECTRIC FLAsH BULB FOR USE AS INDICATOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an electric flash bulb for use as an indicator having an envelope which becomes colorfully colored upon ignition.

2. Description of the Prior Art As is well known, among the problems encountered in the maintenance of electric power transmission lines spectionswere very inconvenient, as climbing to the towerinherently involves a degree of risk to the worker. Such an inconvenience can be dissolved by I providing a photoelectric flash lamp in the discharge circuitof the tower, so that when an electric discharge occurs because of a flow of the energy of abolt of lightning into the tower, the flash lamp is ignited, and the inner bulb wall of the flash lamp becomes discolored thereby. Therefore, the maintenance workers could inspect the faults of transmission lines by locating the discolored flash bulb in the discharge circuit of the respective tower.

But, in the case of presently available conventional photoelectric flash lamps employed as indicators, there are many defects, such as, for example, the inner wall of the bulb not being adequately discolored for. ready observation from a distance, and even if coloring agents are used, the ignition thereof becomes too weak.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to providean improved electric flash bulb for useas an indicator having alight pervious envelope being sealed.

to enclose a mixture of agents comprising coloring agents and oxidizing agents, for adhering on the inner wall of the envelope, such coloring agents being adapted to be scattered by the explosion caused by ignition of combustible material provided in the envelope. 1

Another object of the present invention is to provide an improved flash bulb for use in the maintenance of electric power transmission lines, traffic signal systems,

' for inspection of leakage of electricity, or in measurebodiments of this invention; and,

ignition, the coloring agents are coated on the inner surface of the bulb to radically change the color to permit easy discrimination of the change. Additionally, an uneven acrylic synthetic resin film is coated on the inner surface of the bulb for improving the adhering characteristics of the coloring agents thereto, and another coating of acrylic synthetic resin is applied to the outer surface of the bulb for protecting the same and making it more durable.

BRIEF DESCRIPTION OF Til-IE DRAWINGS Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description, when considered in connection with the accompanying drawings, wherein like reference numerals designate like or corresponding parts throughout'the several FIGURES, and in which:

FIG. 1 is a front, partially cross-sectional, view of an electric flash'bulb constructed in accordance. with the present invention; i FIGS. 2 to 4 are front views of several different em- FIGS. 5 and 6 are enlarged partial cross-sectional views of the bulb wall of other embodiments of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and more particularly to FIG. 1, an electric flash bulb is shown having a glass bulb l as a sealed light pervious envelope coated with a synthetic resin film 2 on the outer surface thereof as a protector, and on the top portion of the inside wall of the envelope, there is adhered a lump 3 composed of a mixture of agents.

The mixture of agents or lump 3, consists of a coloring agent, such as a chemical dyestuff, for example,

rhodamine, para red (para nitro aniline red), indigo 1 pure (trademark of B.A.S.F.), auramine or methylene blue, and an oxidizing agent, for example, potassium chlorate (KClO potassium'perchllorate (KCIO lead dioxide (PbO or manganese dioxide (MnO coupled with a binder, for-example, nitrocellulose, or the like. These coloring agents are combustible materials, while the oxidizing agents have the ability of assisting in the combustion of combustible materials, such as dyestuff.

The mixture ratios of the coloring agents, the oxidizing agents and the binder are shown in the following table, indicated as Table 1.

TABLE 1 Color of I agents coloring agents oxidizing Agents Binder red rhodamine 25% potassium chlorate 25% 15% para red 35% blue methylene blue 20% potassium chlorate 30% IO% indigo pure 40% green methylene blue 20% indigo pure 30% 10% potassium chlorate 30% auramine 10% While they are not necessarily mixed precisely according to the rates indicated, the rates appearing in Table 1 are those which have been found to be most suitable for achieving the objects of this invention.

Enclosed within the bulb are small wires or small pieces or films of aluminum (Al) or zirconium (Zr) as a charge of combustible materials 4, and a pair of lead wires 6 having a filament 7 connected to the tops thereof and coated primers 8 at the points of connection of the filament 7 and the lead wires 6. Oxygen is also enclosed within the bulb as a combustionpromoting gas, and other inactive gases, such as, for example, nitrogen gas (N) or argon gas (A), are also enclosed as combustion-suppressive gases having such properties for suppressing to a suitable low temperature the temperature of the inner space of the bulb. For example, the quantity of combustion-suppressive gas may be up to percent of the volume as compared with that of oxygen. The envelope is mounted on a base 9 being provided with electrodes 10 and 11 for supplying electric current to the bulb.

In the operation of the embodiment shown in FIG. 1, the flash bulb-is ignited by the primers 8 adhered to the connecting points of the filament 7 when a current flows to the filament 7. The charge of combustible material 4 is burned by the primers 8 with oxygen, whereupon light energy and thermal energy are produced. In this case, such action of the flash bulb is accomplished by using thermal energy, but a part of the coloring agents is burned, and almost all of it is evaporated.

FIG. 2 illustrates another embodiment of this invention being shaped as a conventional incandescent lamp type bulb and being similar to the embodiment illustrated in FIG. 1, which has a particularly long portion 12 extended from at least one of the lead wires 6, and in which the mixture of agents 3 are adhered to this long portion 12.

FIG. 3 illustrates another embodiment of this invention in which the flash bulb 1 has enclosed therein many pieces of colored paper 13. The mixture of agents 3 are in this case adhered to both of the lead wires 6 on the middle portions thereof as the ignitor 5. Thus, when the filament 7 is ignited by an electric current, the primers 8 burn, and then the colored papers 13 burn with the combustion-promoting gas, and are caused to disappear, whereby, for example, if the color of the colored paper is red, and the color of the coloring agent obtained by ignition is blue, the flash bulb is discolored from red to blue. Therefore, an inspector can clearly discriminate the bulb in which such discoloration has occurred.

Yet another embodiment of flash bulb is illustrated in FIG. 4, beingof the baseless type incandescent lamp,

which particularly comprises a filament 7 having the mixture of agents 3 directly adhered thereon as the ignitor 5. If this filament is ignited by an electric current, the mixture of agents burns without a combustionpromoting gas.

Still another embodiment of a flash bulb is illustrated in a partially enlarged cross-sectional view in FIG. 5, wherein the bulb wall is improved by coating the inside surface thereof with an acrylic resin film 14 for providing an uneven surface on the inner surface of the bulb. A bulb wall having an uneven surface canprovide-improved adhesive characteristics. Thus, to provide improved coloring, upon evaporation of the coloring agents, the agentsmust be well adhered to the inner surface of the envelope, and since the film 14 becomes soft from the heat attending the combustion of the flashing, the coloring agents therefore are well adhered thereto. The synthetic resin film also serves to prevent explosion of the bulb.

If the ratio of enclosed quantity of inactive gas to the quantity of oxygen as a combustion promotive gas is less than 15 percent by volume, the temperature in the bulb will rise too high, and the coloring agents will be carbonized by the combustion thereof. Also, it is possible that the synthetic resin film 14 would be fully melted by the combustion.

A conventional flash bulb for taking photographs has previously been coated on its outer surface with a vinyl chloride synthetic resin film 15, as illustrated in FIG. 6, which cannot be used outdoors because of discolorizing and stiffening after one or two years from exposure to ultra-violet radiation and weather. If the bulb is covered with a glass cover, however, it becomes too large and too expensive. In order to avoid these defects, the outer surface of the bulb may be coated with an acrylic synthetic resin film having a thickness of more than 5 microns, or an acrylic resin film may be coated directly over the vinyl chloride synthetic resin film coated on the outer surface of the conventional flash bulb. Then, the bulb is made weatherproof.

The test results'of the conventional bulb and of the bulb coated with an acrylic resin film appear in the following Table 2. The testing conditions were:

Testing equipment compulsory weatherproof testing equipment used in the weathering meter of the sunshine type;

Thickness of the acrylic resin film on the outer surface of the bulb 100 microns;

Humidity percent;

Temperature 63i5C.;

Ultra-violet radiation up to 8 mm W per cm.; Rain fall 18 minutes per 2 hours cycle.

TABLE 2 Testing hours Results conventional bulb surface is not changed 300 one l (Jartially brownized 1,000 bIa'c and brownized This embodiment 100 surface is not changed 300 surface is not changed 1,000 some brownized at the surface radiated by lamp possible in light of these teachings. It is to be understood therefore that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

What is claimed as new and intended to be covered by letters patent is:

1. An electric flash bulb for use as an indicator comprising:

an envelope of light previous material; coloring means including a mixture of agents comprising coloring agents and oxidizing agents sealingly enclosed within said envelope; dispersing means within said envelope for dispersing said coloring means throughout said envelope through the release of themal energy and for thereby'coloring the interior of said envelope;

2. An electric flash bulb for use as an indicator, as defined in claim 1, wherein said ignition means comprises a filament, and said mixture of agents is directly adhered on said filaments.

3. An electric flash bulb for use as an indicator, as defined in claim 1, further comprising:

an acrylic synthetic resin film coated on the outer surface of said envelope.

4. An electric flash bulb for use as an indicator, as defined in claim 3, wherein said coatingof acrylic synthetic resin on the outer surface of said envelope has a thickness of at least 5 microns.

5. An electric flash bulb for use as an indicator, as defined in claim 1, wherein said ignition means comprises a filament and atleast a pair of leads connected thereto and said mixture of agents is directly adhered to said 6 leads.

6. An electric flash bulb for use as an indicator, as de- I fined in claim 1, wherein said ignition means comprises a filament and at least a pair of leads connected thereto, and said mixture of agents is directly adhered to an extension of one of said leads.

7. An electric flash bulb for use as an indicator, as defined in claim 1, wherein said mixture of agents is di rectly adhered to the inner wall surface of said envelope.

8. An electric flash bulb for use as an indicator comprising:

an envelope of light pervious material;

a mixture of agents comprising coloring agents and oxidizing agents sealingly enclosed within said envelope;

ignition means disposed in said envelope, whereby said coloring agents are coated on the inner wall surface of said envelope by said ignition means upon combustion; and colored paper enclosed in said envelope, the color of said colored paper being different from that obtained by said coloring agents. =l 

2. An electric flash bulb for use as an indicator, as defined in claim 1, wherein said ignition means comprises a filament, and said mixture of agents is directly adhered on said filaments.
 3. An electric flash bulb for use as an indicator, as defined in claim 1, further comprising: an acrylic synthetic resin film coated on the outer surface of said envelope.
 4. An electric flash bulb for use as an indicator, as defined in claim 3, wherein said coating of acrylic synthetic resin on the outer surface of said envelope has a thickness of at least 5 microns.
 5. An electric flash bulb for use as an indicator, as defined in claim 1, wherein said ignition means comprises a filament and at least a pair of leads connected thereto and said mixture of agents is directly adhered to said leads.
 6. An electric flash bulb for use as an indicator, as defined in claim 1, wherein said ignition means comprises a filament and at least a pair of leads connected thereto, and said mixture of agents is directly adhered to an extension of one of said leads.
 7. An electric flash bulb for use as an indicator, as defined in claim 1, wherein said mixture of agents is directly adhered to the inner wall surface of said envelope.
 8. An electric flash bulb for use as an indicator comprising: an envelope of light pervious material; a mixture of agents comprising coloring agents and oxidizing agents sealingly enclosed within said envelope; ignition means disposed in said envelope, whereby said coloring agents are coated on the inner wall surface of said envelope by said ignition means upon combustion; and colored paper enclosed in said envelope, the color of said colored paper being different from that obtained by said coloring agents. 